以表面粗化技術提升氮化鎵發光二極體效率之介紹

Introduction to the Enhancement of Efficiency in LEDs Using Surface Roughening Techniques

許進恭(Jinn-Kong Sheu) ； 李明倫(Ming-Lum Lee) ； 許永儒(Yong-Ru Xu)

《光學工程》 90期 (2005/06) Pp. 29-37

https://doi.org/10.30011/OE.200506.0004

摘要

LED光源具有節省能源、環保與堅固耐用等優點，因白光LED具有取代傳統照明的潛力。但達成此一目標所面臨的最大挑戰－價格及效率。雖然製作白光LED的方式有很多種，但不管是任何形式的白光LED，其效率之高低主要取決於激發源（亦即LED晶粒）之效率，雖然四十年來LED的效率已增加數百倍，但若要取代現有之日光燈仍有一段距離，因此如何將LED的效率再往上推進，乃是從事LED相關研究者所面臨的重要課題，而影響LED效率的因素有很多其中包括磊晶層結構設計與成長、晶粒製程及封裝。以晶粒製作階段而言，如何增進光子之淬取率，實為提升LED效率的最重要課題，本文將針對此課題作一概略探討。

關鍵字

氮化鎵 ； 磷化鋁鎵銦 ； 光淬取效率 ； 表面粗化 ； 發光二極體

並列摘要

Light-emitting diodes (LEDs) have become as bright and efficient as conventional incandescent bulbs. They have already begun to replace incandescent bulbs in many applications, particularly those requiring durability, compactness, and/or directionality (e.g., traffic, automotive, display, and architectural directed-area lighting). However, LEDs are over two orders of magnitude more expensive than commercial incandescent light bulbs for general illumination. This high cost issue is a main barrier for LEDs replacing nowadays lighting fixtures. Threrfore, further major improvements are believed achievable? Electrical-to-optical energy conversion efficiencies over 50% have been achieved in LEDs emitting wavelengths around 600nm. If similar efficiencies were achieved in blue, green and UV LEDs, the result would be a 100 lm/W white light source. The efficiency would be comparable with those of fluorescent lamps, and 5 times, at least, more efficient than incandescent lamps. It is well known that the limited light extraction efficiency of LEDs is due to absorption within the LED material, the Fresnel loss and the critical loss. In this article, the authors introduce a number of approaches including surface roughening techniques on the improvement of light extraction efficiency in LEDs.

並列關鍵字

GaN ； AlGaInP ； Light-extraction efficiency ； surface roughening ； LED